If I were an F/O in a situation where the aircraft was descending through 500 ft at 180 kts with only 15 degrees of flap (or whatever the scenario might be) and I thought a crash at the other end of the runway was looking inevitable, I would simply reach for the gear selector and select "GEAR UP"!
If we're talking about "Emergency Language" from the F/O being completely ignored or dismissed by the Captain and lives are at stake, this would be the alternative to taking control of the aircraft.
I don't see how the approach could possibly be continued from that point unless the Captain was completely insane.
[Ha! You beat me by one minute!]